Biology > Excretion > Flashcards

Excretion Flashcards

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1
Q

Define excretion

A

Getting rid of waste due to chemical reactions/metabolism

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2
Q

Define homeostasis

A

Maintenance of a constant internal environment in an organism

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3
Q

Define metabolism

A

Sum of all chemical reactions in the body

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4
Q

Define egestion

A

Removal of unabsorbed, undigested material

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5
Q

Name some organs of excretion

A
  • Lungs
  • Skin
  • Kidneys
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6
Q

What do the lungs excrete?

A

CO2

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7
Q

What does the skin excrete?

A

Sweat

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8
Q

What do the kidneys excrete?

A

Urea from protein breakdown

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9
Q

How and where is urea made?

A

In liver through deamination

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10
Q

Name some structures of excretion in plants

A
  • Stomata
  • Lenticels
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11
Q

What excretory processes occur in plants?

A
  • Transpiration
  • Diffusion
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12
Q

Name a structure of excretion in amoeba?

A

Contractile vauole

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13
Q

By what process do unicellular organisms excrete?

A

Diffusion

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14
Q

Draw and label the structure of the skin

A
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15
Q

What are the names of the layers of skin?

A

Outer epidermis and inner dermis

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16
Q

What is the name of the layer below the dermis?

A

Adipose layer

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17
Q

What is the adipose layer made up of?

A

Fat-rich cells

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18
Q

What occurs in the malphigian layer?

A

Cell division occurs to produce new epidermal cells and melanin

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19
Q

How long is the cycle of cell division in the malphigian layer?

A

Two to three weeks

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20
Q

What occurs in the granular layer?

A

Cells move out towards surface and produce keratin

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21
Q

What does keratin cause?

A

Causes the cells to become hardened

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22
Q

What happens in the cornified layer?

A

There are no capillaries so the cells die. These cells then continually wear away

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23
Q

What is melanin?

A

Pigment which varies in colour from light brown to black in different people. This gives our eyes, hair, and skin colour

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24
Q

What is the function of melanin?

A

Protects the skin from harmful ultraviolet rays from the sun

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25
How does tanning occur?
The skin is exposed to the sun's rays which increases the production of melanin
26
What is the role of the epidermis?
* The malphigian layer is where cell division takes place to produce new epidermal cells. This cycle lasts about two or three weeks. * Also in the Malpighian layer are cells that produce melanin which is responsible for skin and hair colour * As these cells move out toward the surface they produce a protein called keratin in the granular layer * This protein causes the cells to become hardened. * There are no capillaries in the cornified layer of the skin so the cells die. These cells continually wear away
27
What type of tissue is the dermis?
Live connective tissue
28
What is the function of collagen?
Helps strengthen the skin
29
Where in the skin is collagen found?
Dermis layer
30
Give some functions of the skin
* Protects against physical injury * Sebum, produced in the sebaceous glands, keeps the hair moist and prevents the drying out of the skin. It also protects against many pathogenic microbes and and chemical agents * Fat in the adipose layer acts as a food store * Sensory organ for temperature, pressure, touch, and pain * Melanin protects underlying tissues from UV rays * Plays a role in metabolism, including vitamin D synthesis following the exposure to ultraviolet light. * Acts as an organ of excretion. Sweat contains water and salts. Sweat glands pass these out of the sweat pores. * Plays a major part in the temperature regulation of the body.
31
Where is sebum produced?
Sebaceous glands
32
What is the function of sebum?
* Keeps hair moist and flexible * Prevents drying out of skin * Provides protection for body against many pathogenic microbes and chemical agents
33
What is a function of fat in the adipose layer?
Acts as a food store
34
What does a lack of vitamin D cause?
* Soft bones that may bend under the weight of the body and may result in bowed legs called rickets
35
What does sweat contain?
Water and salt
36
How is sweat excreted?
It is passed out by sweat glands through sweat pores
37
What are the two different ways that organisms can regulate body temperature?
Endotherms: Warm blooded and generate their own heat from respiration, food, etc Ectotherms: Cold blooded and temperature varies according to the environmental temperatures
38
Give an example of an endotherm
Human
39
Give an example of an ectotherm
Frog, snake
40
Explain some adaptions of the skin in cold conditions
* Piloerection: Producing goose pimples/bumps. Tiny erector muscles at the base of each hair contract and pull the hair erect. This reflex is started by the sympathetic nervous system which is in general responsible for many fight or flight responses. The erect hairs trap air to create a layer of insulation. * Vasoconstriction: Arterioles in the skin contract as as to reduce heat loss * Shivering: When the core temperature of the body drops, the shivering reflex is triggered in an attempt to create warmth by expending energy * Fat in the adipose layer insulates our bodies
41
What part of the body detects cold conditions?
Hypothalamus in the brain
42
Explain piloerection
* Producing goose pimples/bumps. * Tiny erector muscles at the base of each hair contract and pull the hair erect. * This reflex is started by the sympathetic nervous system which is in general responsible for many fight or flight responses. * The erect hairs trap air to create a layer of
43
Explain vasoconstriction
Arterioles in the skin contract as as to reduce heat loss
44
What part of the body detects warm conditions?
Hypothalamus in the brain
45
Explain some adaptions of the skin in warm conditions
* Sweat is produced and released. The evaporation of the sweat cools our bodies as the heat is released from the sweat * Vasodilation: Arterioles in our skin dilate and more heat from the blood is released
46
Draw and label a diagram of the urinary system
47
What is the function of the kidney?
* Excretes urine * Osmoregulation * pH control
48
What does urine contain?
* Urea * Water * Salts
49
What is the function of osmoregulation?
Maintains stable balance of water and dissolved salts
50
Where are the kidneys located?
Abdomen
51
What is the function of the bladder?
Stores urine
52
What organ is the sphincter muscle a part of?
Bladder
53
What is the function of the ureter?
Carries urine from the kidney to the bladder
54
What is the function of the urethra?
Carries urine out of the body
55
What is the function of the renal vein and the renal artery?
Blood supply for the kidneys
56
Draw and label a diagram of the kidney structure
57
What is the function of the medulla?
Reabsorption
58
What is the function of the cortex?
* Filtration * Secretion * Reabsorption
59
What is the function of the pelvis?
Drains out urine to the ureter
60
What is the role of the nephron?
Functional unit of the kidney
61
Where is the nephron located?
Kidneys
62
Draw and label a diagram of the nephron
63
Explain filtration in the nephron
* Blood is pumped from the heart through large blood vessels to the kidneys via the afferent arteriole (containing waste products). * Inside the kidney there are blood vessels known as capillaries. The glomerulus is the filtering unit and contains a cluster of leaky capillaries. The filtrate (glomerular filtrate) collects into a sac called Bowman’s capsule and drains into the proximal convoluted tubule. * The tiny capillaries filter minerals, glucose, amino acids, vitamins, hormones, urea, salts and water but retain blood cells, antibodies, proteins and large molecules. This process is known as filtration. The proteins that are not filtered remain in the capillary because they are too big to be filtered out via efferent arteriole. The filtered blood is returned to the body through the veins.
64
How is the glomerulus adapted to its role?
* The high pressure - efferent arteriole is narrower than afferent arteriole * Large surface area of capillaries * Walls of capillaries in glomerulus are more porous * Bowman’s capsule is one cell thick
65
Explain reabsorption in the nephron
* The fluid and its substances must now travel through a long and winding tubular pathway first through the proximal convoluted tubule where most of the useful material (glucose, amino acids, water, salts) is reabsorbed by diffusion, active transport and osmosis * There the tubule makes a sharp hairpin turn called the Loop of Henle * Descending- some water is reabsorbed by osmosis * Ascending- salts reabsorbed by diffusion and active transport * Distal convoluted tubule controls the precise concentration of water, salt and pH values of blood (H+ conc) * A little bit of water is reabsorbed in the collecting duct. This carries the remaining waste products i.e. urine to the pelvis of the kidney and away to the bladder via the ureters.
66
Give adaption of the proximal convoluted tube
* Microvilli to increase surface area * One cell thick * Long * Lots of mitochondria for energy
67
Is the collecting duct an endocrine gland?
No
68
Explain secretion in the nephron
Some substances pass from the blood into the nephron in the proximal and distal convoluted tube to control pH balance
69
What is the difference between glomular filtrate and urine?
* Glomerular filtrate has more water and contains many useful materials for example glucose and amino acids * Urine contains urine, salt, and water
70
How is urine volume controlled?
* ADH travels in the blood to the kidneys if dehydrated. * If overhydrated, plasma is diluted. ADH is not produced and the distal tubules and collecting ducts become impermeable to water
71
What does ADH stand for?
Antidiuretic Hormone
72
What is the importance of homeostasis?
* Essential for optimal enzyme function * Maintains constant conditions in cell * Maintains internal body temperature of 37 degrees celsius * Maintains constant fluid balance * Maintains pH levels
73
Where is most water and salt reabsorbed in the nephron?
Proximal tubule
74
How much water is reabsorbed by the descending limb of the loop of Henle?
A little
75
How much salt is reabsorbed by the descending limb of the loop of Henle?
None
76
How much water is reabsorbed by the ascending limb of the loop of Henle?
None
77
How much salt is reabsorbed by the asccending limb of the loop of Henle?
Some
78
How much water is reabsorbed by the distal tubule?
Some
79
How much salt is reabsorbed by the distal tubule?
Some
80
How much water is reabsorbed by the collecting duct?
A little
81
How much salt is reabsorbed by the collecting duct?
None
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